1. Technical Field
The present invention relates to a technology for selecting a vehicle (preceding vehicle) that is traveling ahead of an own vehicle.
2. Related Art
As a technology for reducing operating load placed on a driver who is driving a vehicle, an inter-vehicle control apparatus is known. The inter-vehicle control apparatus detects a vehicle (preceding vehicle) that is traveling ahead of the own vehicle. The inter-vehicle control apparatus controls the vehicle speed and the like to maintain a certain distance between the own vehicle and the preceding vehicle, enabling the own vehicle to automatically track the preceding vehicle.
In this type of apparatus, a radar or the like is used to detect objects that are present ahead of the own vehicle. The preceding vehicle that should be tracked by the own vehicle is selected from among the detected objects. When making the selection, there is a technology (refer, for example, to JP-B-4904983) for improving determination accuracy regarding whether or not the detection result of a previous cycle and the detection result of a current cycle are based on the same vehicle. The technology uses, among a plurality of pieces of position information that are clustered as pieces of position information that are based on the same target, the position information indicating an end portion position of the target that is closest to the own vehicle (referred to, hereinafter, as an “end portion position information”), rather than the position information indicating another specific position (such as the center) of the target (referred to, hereinafter, as a “specific position information”).
When determination is made regarding whether or not a target that is present ahead of a vehicle is a preceding vehicle based on position information of the target, use of the end portion position information can be considered to enable the determination to be made earlier. In other words, the end portion position indicated by the end portion position information is closer to the own vehicle than the specific position indicated by the specific position information. Therefore, determination of whether or not the object is present in the own vehicle lane can be made earlier.
As described above, individual pieces of position information that have been clustered for the same target are used as the end portion position information. However, the end portion position information can also be predicted from the specific position information and width information (lateral width of the area in which the clustered pieces of position information are present) of the target detected by a radar.
However, the specific position information (in particular, a lateral position indicating the position in the vehicle width direction) of the target detected by a radar or the like does not accurately indicate a specific position (such as the center of the vehicle). The specific position information varies. In addition, error in a predicted path on which the own vehicle travels increases as the distance increases. Error in the width information increases as the radius of curvature of the path decreases (becomes a sharp curve). Therefore, when the end portion position information predicted from the specific position information and the width information is used to select and cancel a preceding vehicle, a problem occurs in that erroneous selection easily occurs.